In the “Expression” input box at the top of the web page, enter the text: istio_request_count. Then, click the Execute button.

The results will be similar to:

Prometheus Query Result

Other queries to try:
- Total count of all requests to `productpage` service:
```
istio_request_count{destination_service="productpage.default.svc.cluster.local"}
```
- Total count of all requests to `v3` of the `reviews` service:
```
istio_request_count{destination_service="reviews.default.svc.cluster.local", destination_version="v3"}
```
This query returns the current total count of all requests to the v3 of the reviews service.
- Rate of requests over the past 5 minutes to all `productpage` services:
```
rate(istio_request_count{destination_service=~"productpage.*", response_code="200"}[5m])
```

About the Prometheus Add-on

Mixer comes with a built-in Prometheus adapter that exposes an endpoint serving generated metric values. The Prometheus add-on is a Prometheus server that comes pre-configured to scrape Mixer endpoints to collect the exposed metrics. It provides a mechanism for persistent storage and querying of Istio metrics.